1. Field of the Invention
The present invention relates to an audio processing apparatus, an audio processing method and an imaging apparatus.
2. Description of the Related Art
With the recent digitalization of imaging apparatuses such as cameras, various sensors are incorporated in imaging apparatuses. Examples of such sensors include a microphone for detecting audio, a shake detection sensor for detecting a shake, a focus detection sensor for detecting the distance to a subject, and the like. These sensors are required to obtain stable detection signals.
Meanwhile, with imaging apparatuses such as cameras, there are cases where it is not possible to properly obtain sensor signals for a certain period of time due to adjustment of an optical system. For example, there are cases where audio from a subject cannot be properly obtained due to sound generated during the diaphragm closing operation. As described above, if sensor signals are not properly obtained, it leads to a decline in performance of the imaging apparatus and a decline in quality of captured information. In order to solve these problems, various signal processing circuits and imaging apparatuses have been proposed.
For example, Japanese Patent Laid-Open No. 03-295400 discloses an imaging apparatus that removes noise from audio signals by using a reference sensor and an adaptive filter. Also, Japanese Patent Laid-Open No. 2008-053802 discloses a method for processing audio signals in which an audio pitch near a brief noise is detected and a predictive signal is properly generated.
However, the conventional techniques described above are problematic in that a component is required for performing appropriate processing in the case where a situation occurs briefly in which only inappropriate signals are obtained, or the load is intensively transmitted at a specific timing. For example, the method disclosed in Japanese Patent Laid-Open No. 03-295400 requires a sensor for obtaining the reference signal of the adaptive filter. Also, the method disclosed in Japanese Patent Laid-Open No. 2008-053802 requires detection of the pitch and generation of the predictive signal at the occurrence of a noise, resulting in concentration of a computational load.